French and Kirkland (1983) concluded from morphological data that S. dispar and S. gaspensis are not conspecific. However, the only significant difference between the two taxa is size, with S. gaspensis smaller than S. dispar (Kirkland and Van Deusen 1979, French and Kirkland 1983). Yet Sorex dispar exhibits a south to north decreasing cline in body size, suggesting the possibility that S. gaspensis is not a distinct species but rather simply represents the northern extent of the S. dispar cline. Accordingly, Rhymer et al. (2004) found that the apparent distributional gap between S. dispar and S. gaspensis is not as large as previously believed (if in fact it exists at all) and that a morphological cline between dispar and gaspensis cannot be ruled out. Additionally, using mtDNA d-loop sequences, Rhymer et al. (2004) found that S. gaspensis and S. dispar cluster with no taxonomic or geographic structure, suggesting that they are conspecific. Hutterer (in Wilson and Reeder 2005) considers S. dispar to be distinct but this is probably because Rhymer et al. (2004) was published too late to be considered by Hutterer (in Wilson and Reeder 2005).

This species occurs in the Appalachian Mountains, from Nova Scotia (Scott, 1987) and southeastern New Brunswick, Canada southward along the mountains to North Carolina and Tennessee in the United States (Kirkland, in Wilson and Ruff 1999). Recent data indicate that populations formerly recognized as Sorex gaspensis actually should be included in S. dispar, so the range of S. dispar extends northeastward to the Gaspe Peninsula in Quebec and Cape Breton Island in Nova Scotia, Canada (Rhymer et al., 2004).

It is an Appalachian Mountains endemic with a habitat that is not often suited for human use and development. Due to the difficulty of trapping this species, there are probably more occurrences than are currently known. The long-tailed shrew is, therefore, apparently secure and likely stable over most of the range, but few population data are available.

It occurs in mountainous, forested areas (deciduous or evergreen) with loose talus. Rocky damp areas with deep crevices covered by leaf mold and roots are preferred. It may occur along small mountain streams. It will use artificial talus created by road construction and pit mines. Trapping results reported by Richmond and Grimm (1950) suggest that long-tailed shrews spend most of their time in the labyrinth of spaces between rocks about a foot beneath the surface. Nest sites are usually associated with natural subterranean tunnels among boulder crevices. Breeding occurs in spring and summer, possibly late April to August (Kirkland and Van Deuen, 1979). One or two litters may be produced from May through August, with two to five young per litter. Sexual maturity is reached in less than a year. Like other shrews, this species probably does not survive beyond about 18 months.

The shrew's partly subterranean existence among rocks makes observation, direct or indirect, very difficult. Virtually all data comes from trapping. Nothing is known of territoriality or home range size. The same predators that feed on other shrews probably take long-tailed shrews, e.g., weasels, snakes, hawks and owls, but there is no specific information. External parasites include fleas, ticks, mites and chiggers. While no internal parasites have been reported, nematodes and tapeworms are common in other shrew species. Examination of the digestive tracts of long-tailed shrews indicates a diet primarily of small invertebrates. Some better-known species of shrews are reported to consume approximately their own weight in food daily, and, with their high metabolic rates, may die within a few hours when deprived of food.

Overall there are no major threats to this species throughout its range. Habitat destruction is a localised threat, but less so than for many rare species because the preferred habitat, talus, is often unsuitable for development, and provides a very uniform subterranean environment that is not highly vulnerable to disturbance. However, ski area expansion may be a threat to some populations, as in Vermont (Fichtel pers. comm., 1992). Highway construction may create more habitat than it destroys, as long-tailed shrews have been collected in the artificial talus slopes of road cuts (Conway and Pfitzer, 1952). Logging is unlikely to adversely impact this shrew; Kirkland (1979) showed that shrews persisted in recently clearcut red spruce stands in West Virginia. Shrews feed on invertebrates and may accumulate and concentrate pesticides and heavy metals in their tissues.

Many populations are in national forests, parks, or other public lands, and many are in areas protected by their remoteness. Protection of habitat from gross disturbance is the primary protection need. Habitats for these shrews should be protected from contamination by heavy metals and pesticides.